C8051F410DK Silicon Laboratories Inc, C8051F410DK Datasheet - Page 208

• Manufacturer Part Number: C8051F410DK
• Description: KIT DEV FOR C8051F41X
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051F410DK

• Contents: Evaluation Board, Power Supply, USB Cables, Adapter and Documentation
• Processor To Be Evaluated: C8051F41x
• Interface Type: USB
• Silicon Manufacturer: Silicon Labs
• Core Architecture: 8051
• Silicon Core Number: C8051F410
• Silicon Family Name: C8051F41x
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: Silicon Laboratories C8051F41x
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1314

C8051F410/1/2/3
22.1. Enhanced Baud Rate Generation
The UART0 baud rate is generated by Timer 1 in 8-bit auto-reload mode. The TX clock is generated by
TL1; the RX clock is generated by a copy of TL1 (shown as RX Timer in Figure 22.2), which is not user-
accessible. Both TX and RX Timer overflows are divided by two to generate the TX and RX baud rates.
The RX Timer runs when Timer 1 is enabled, and uses the same reload value (TH1). However, an
RX Timer reload is forced when a START condition is detected on the RX pin. This allows a receive to
begin any time a START is detected, independent of the TX Timer state.
Timer 1 should be configured for Mode 2, 8-bit auto-reload (see
ter/Timer with Auto-Reload” on page 233
occur at two times the desired UART baud rate frequency. Note that Timer 1 may be clocked by one of six
sources: SYSCLK, SYSCLK / 4, SYSCLK / 12, SYSCLK / 48, the external oscillator clock / 8, or an exter-
nal input T1. The UART0 baud rate is determined by Equation 22.1-A and Equation 22.1-B.
Where T1
auto-reload mode reload value). Timer 1 clock frequency is selected as described in
on page 231
through Table 22.6. Note that the internal oscillator may still generate the system clock when the external
oscillator is driving Timer 1.
208
CLK
. A quick reference for typical baud rates and system clock frequencies is given in Table 22.1
is the frequency of the clock supplied to Timer 1, and T1H is the high byte of Timer 1 (8-bit
Detected
Start
A)
B)
Figure 22.2. UART0 Baud Rate Logic
UartBaudRate
T1_Overflow_Rate
RX Timer
Equation 22.1. UART0 Baud Rate
Timer 1
TH1
TL1
). The Timer 1 reload value should be set so that overflows will
=
Overflow
Overflow
Rev. 1.1
1
-- -
2

=
T1_Overflow_Rate
------------------------- -
256 TH1
T1
–
CLK
2
2
Section “24.1.3. Mode 2: 8-bit Coun-
UART
RX Clock
TX Clock
Section “24. Timers”